This paper describes the design issues of direct conversion RF receivers for WLAN systems using SiGe technology. For direct conversion transceivers, SiGe BiCMOS technology offers a combination of enhanced RF performance with advanced silicon technology. Simulated performance parameters of an active direct down conversion mixer using SiGe BiCMOS MMIC technology are presented. The mixer functions at 5 GHz and draws only 10.2 mW from a 3 V supply. The overall conversion gain of the circuit is 8.5 dl3.